RESUMO
Complex chromosomal rearrangements are rarely observed prenatally. Genetic counceling of CCR carriers is complicated, especially in cases of de novo origin of the rearrangement. Here we present a new case of a de novo CCR involving four chromosomes observed in amniotic fluid cells of the fetus at 17 weeks of gestation. The rearrangement was characterized as an apparently balanced four-way translocation t(1;11;7;13)(~p21;~q13.5;~q32;~q22)dn by conventional cytogenetic studies. However, array-based comparative genomic hybridization revealed 5 submicroscopic heterozygous interstitial deletions on chromosome 1, 11, 7, 13 with a total loss of 21.1 Mb of genetic material in regions close to those, designated as breakpoints by conventional cytogenetic analysis. The described case clearly illustrates that high-resolution molecular genetic analysis should be combined with conventional cytogenetic techniques to exclude subtle chromosomal abnormalities in CCR cases detected prenatally.
Assuntos
Líquido Amniótico/citologia , Cromossomos Humanos Par 11/química , Cromossomos Humanos Par 13/química , Cromossomos Humanos Par 1/química , Cromossomos Humanos Par 7/química , Translocação Genética , Amniocentese , Hibridização Genômica Comparativa , Feminino , Feto , Idade Gestacional , Humanos , Hibridização in Situ Fluorescente , Cariotipagem , Masculino , Gravidez , Segundo Trimestre da Gravidez , Adulto JovemRESUMO
To assess the frequency and structure of chromosomal abnormalities in patients with infertility, a retrospective analysis of cytogenetic studies of 3414 patients (1741 females and 1673 males), referred to the Clinic of reproductive medicine "Nadiya" from 2007 to 2012, was performed. Chromosomal abnormalities were detected in 2.37% patients: 2.79% in males and 1.95% in females. Balanced structural chromosomal abnormalities prevailed over numerical abnormalities and corresponded to 80.2% of all chromosomal abnormalities detected in the studied group. Sex chromosome abnormalities made up 23.5% of chromosomal pathology (19/81) and included gonosomal aneuploidies in 84% of cases (16/19) and structural abnormalities of chromosome Y in 16% of cases (3/19). The low level sex chromosome mosaicism was detected with the frequency of 0.55%. Our results highlight the importance of cytogenetic studies in patients seeking infertility treatment by assisted reproductive technologies, since an abnormal finding not only provide a firm diagnosis to couples with infertility, but also influences significantly the approach to infertility treatment in such patients.
